Mode of manufacturing inner tubes



vv. W, WHLDMAN vMODE OF MANUFACTURING INNER TUBES Filed June le, 1921 (Il. a.'

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@wuz nto'` ww. w LEMAN LfuLMmM- Patented Jing. if, p w23.

Wimmer@ W. WiLDMAu, or :ser

`\\` RUBBER COMPANY, or :BAY CITY,

MDE F MANUFACTURNG INNER ing 'inner tubes for pneumatic tires, and' particularly inner tubes .composed entirely of rubber in which a portion of the rubber is non-vulcanizable and adapted to Aseal cuts .15 or punt-.tures in the treed side of the tube.. n

The attached Vdrawing; illustrates the steps teken to make the tube, Fig. l being"r a perspective View showing the first steps of laying threeplics or strips ot' rubber leugthwise one upon the other. Fig. 2 is a perspcc` tive view ot a mandrel placed upon the as sembled plies of rubber. Fig. 3 is a perspec-v tive View of the seversl plies folded or rolled around tht mandrel, and showingt a portion thereof compressed tightly within the spiral folds ot' e muslin wrapper. Fig.

4 is a sectional View. showing the tube being' y turned inside out While it is being stripped i from the mandrel. Fig. '5 is a cross section of the finished tube showing its normal shape "when not inflated..

In making this tube, a relatively long' sheet or strip 2 of rubber of e predetermined width is laid. Het upon a. table, and this sheetot rubber contains sulphur or an equivalent -vulcanizing ingredient. A second narrower strip 3 of rubber one-eighth to one-fourth of fen inch in thickness is thenleid lengthwise upon the middle portion of sheet 2, and this strip is mede ofi ruw crude gum or rubber in Vwhich no sul bur or vulcanizing ingredient has been'ad ed. A third sheet or strip 4:

of vulcanizable rubber of approximately the sume width but relatively thicker than the first strip -2 is then laid upon the strip 3 in overlappmg position upon the exposed parts of bottoni strip 2, all three pieces of rubber 5 being of approximately the sume length end also plastic and of e consistency to cause te them to adhere to eachother. 'lhe 4uuiddle strip 3 is especially viscous or sticky and iuuch es no vulceuisiug substence is mired et'tlie'iihieetin'g edges and feces.

lltlll aila CITY, Ml'CHIGANfASSGNOR T0 THE WILDMAN MICHGAN, A CRPRATION 0F DELAWARE.

TUBES. g

Application led June 1S, 1931. Serial No. @$8,055.-

therewith it remains nV tbatcondition after the other two strips have been vulcanized.

The next A other shaped mandrel 5 upon the top side of the assembled rubber strips und wrap, roll or-told the three strips jointly around the mandrel until the opposite longitudinal edges of the top end bottom strips abut or @o overlap totorm a tube. A strip@ of cloth` 1s then Wound tightlj,7

p around the three rubber plies on the mandrel to place them-jointly under compression, and the Wrapped product is then placed within :i suitable heater or vulczinizer until strips 2 und Llare vulcanired tl oughout and hornogeneously united The raw gum 3 absorbs some ot the vulcanizingr material in the other two plies or rubber so that 20 all three plies are actually united together while still leavingr the inner or larger volume ot' crude rubber in its raw tacky state. The tube is then removed from the mandrel and turned inside out to stretch the elastic thicker ply 4 ot rubber 'around the outside otthe interluyer ofcrudc adhesive rubber, thereby placing the adhesive rubber in u con stant state ot compression. l` he turned tube is ythen spliced et its opposite ends to form 804 an annuler or ring-shaped tube of the desired diameter for use Within a tire-clisiug hav infr e corresponding inner diumetler. An air ve, ve is also efxed to the tube in the. custo? mary way o permit the tube to be inflated e5 und'ueed in pneumatic tire casings ofvany description.-v

-A tube' made according to this method is more durable and lasting than the inner tubes in Agenera-l use and can be produced e0 lnearly es cheaply, and in addition the tube posseesv the valuable property and cher4 scteristic of seeding and repairingr itself when puncturedl What l clein iis:

A mode of manufacturing. inner tubes for tires, consisting iii laying a'- relatively'long strip of rubber containing a vulcanizing substance upon e Het surface; in laying; e second narrower strip .lengthwise upon seid tiret strip; in su erfposing e thirdstrip of vulcanizable rubber upon the other .st'ti'ips;` in placing an elongated mendrel upon the topside of the -asprocedure is to place a round or 55 oi unvulcanizable rubber sembled strips andfolding said strips jointly around the mandrel until the opposlee 10ng1 tudinal edges are engaged and form a tube; in wining a' strip (if fabric tightly around 5 the several plies of rubber on the mandrel;

in subjecting the wrapped product to heat until the vulcuriizable rubber is cured and all the Smid strips are hcnogeneously united ai; their meeting surfaces; in removing the vulcanized tube from the mandrel and turn ing it inside out to place ille interlayer of unvulcanizable rubber in a, constant state of compression; and in splicing the opposite ends of said tube together to form a, ringsliapecl tube adaptecl to be'inflatecl.`

WLLLAM W. WILDMAN n 

